Ball Joint
A ball joint mechanism includes generally a ball within a housing. Often the ball has attached thereto a rod which extends out beyond the housing. An actuator acts between the housing and the ball to fix the position of the ball, and therefore the angle of the rod, relative to the housing. A ball joint mechanism is disclosed, for example, in U.S. Pat. No. 5,280,871 where a plurality of holes are orderly and equally spaced apart in the surface of the ball for accepting the functional end of an actuator pin. A dimpled ball and an actuator having a spherical tip are also shown in U.S. Pat. No. 3,433,510. U.S. Pat. Nos. 3,841,769 and 4,620,813 show a socket having protuberances and a ball having dimples or indentations which engage to fix the orientation of rods attached thereto. U.S. Pat. No. 3,691,788 shows a ball having a grooved surface and an actuator having a spherical tip which locks up by engaging a groove. U.S. Pat. No. 892,105 shows a ball and socket whose surfaces are both knurled.
Angularly adjustable, releasably lockable ball joints are commonly used as part of an umbrella assembly, to lock a suspended canopy locked at a selected angle. Assemblies of this type are shown in U.S. Pat. Nos. 4,674,523 and 5,002,081. The frictional engagement of a ball and a socket, as well as a dimpled ball and spherical pin actuator, have been found to be insufficient when subjected to high torsional forces.
Prosthetic Terminal Device Locking Assembly
Terminal devices, such as artificial hands, swimming paddles, etc., are used in association with prosthetic limbs. Such terminal devices are attached by locking assemblies to the prosthetic limb. Known terminal device locking assemblies are difficult to operate, especially by persons who have only one hand.
A typical locking assembly includes a bore formed in the prosthetic limb which accepts and locks an adapted stem on the terminal device. The locking mechanism includes a button that must be actuated both to release the stem from the bore and to insert the stem into the bore. It will be appreciated that the operation of insertion is very difficult since it requires that the stem of the terminal device be inserted into the bore while actuating the button. The insertion operation is further complicated in some prior art embodiments having a stem, the end of which is shaped and must be aligned during the insertion operation with a mating shaped portion within the bore. Such stem/socket mating prevents undesirable rotation of the terminal device but complicates the insertion procedure.